Structure and properties of maleated high‐density polyethylene

Abstract

Abstract Possible changes in the structure and properties of maleated polyethylene (HDPE–MA) at different degrees of grafting (D.G.) were examined. At the level of 1.6 maleic anhydride (MA)/100 ethylene units E, 70–80% of crystallinity of the parent PE was retained (DSC and WAXD). Both melting temperature and crystallization temperature decreased only slightly with increase in D. G. The lattice constants a and b of the orthorhombic PE crystallites remained constant, although c was constantly at a larger value. The presence of MA groups hampered the packing of PE chains, leading to an increase in PE crystallite sizes of L̄ 110 and L̄ 200 with maleation. Of the viscoelastic relaxations, dynamic mechanical analysis showed easier segmental motions and thus lowering in γ‐, α‐ and β‐relaxation temperatures with maleation. The breaking strength (σ b ) increased slightly with maleation, whereas the elongation at break (ε b ) lowered due to interaction between the MA groups. In all, in HDPE‐MA up to a D. G. of 1.6 MA/100 E, PE properties were maintained to be used per se or as a compatibilizer for blends involving PE or in any other usage where retention of PE properties is desired. © 1994 John Wiley & Sons, Inc.